The global climate is changing rapidly and countries need clear direction on how best to adapt to these changes. Ecosystem-based adaptation (EbA) is becoming an increasingly popular strategy, especially in poor countries where dependence on natural resources for lives and livelihoods is high. But EbA implementation is neither widespread nor consistent, partly due to a shortage of documented evidence relating to its effectiveness. This report shares results from research assessing EbA effectiveness at 13 case study sites in 12 countries to help address this gap. It also describes political, institutional and governance-related conditions that facilitate or inhibit effective EbA at each site.